Currently, semiconductors must be produced in a clean vacuum chamber where even presence of micron-sized dust is not permissible. A clean room robot which does not generate dust needs to be employed to transfer silicon wafers in the vacuum chamber, and it is desirable that the wafers are isolated from a semiconductor-manufacturing device during transfer and all processing steps are completed in the hermetically sealed vacuum chamber.
To transfer objects inside such a vacuum or airtight chamber by handling the objects from the exterior of the chamber, for example, a conveying device using superconducting magnetic levitation is favorably employed. For example, Published Japanese Patent Application No. 63-310304 discloses such a magnetic levitation device using superconductivity.
Published Japanese Patent Application No. 63-310304 discloses a technology in which superconductors and a magnet array comprising arranged magnets are repelled each other in order to levitate either one of them. In this instance, one of the magnet array and superconductors, usually the superconductors, are transferred to convey the magnet array (object to be conveyed). In the technology disclosed in the publication, however, when disturbance such as impact occurs on the superconductors, the levitated magnet array vibrates. This causes a problem that the vibration of the magnet array continues permanently because the array is suspended in free space due to pinning effect.